Browsing by Author "Kuan, CH"

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Guided three-dimensional molecular self-assembly on silicon substrates
(2006-06-26)
Chang, CC
;
Sun, KW
;
Kan, LS
;
Kuan, CH
;
生物科技學系
We demonstrate three-dimensional (3D) self-assemble growth of the metallothionein (Mn,Cd-MT-2) molecules on patterned semiconductor substrates. The MT molecules deposited on the patterned substrates were found to grow into 3D rod or ring-type nanostructures, depending on the shape of patterned nanostructures on the substrates. Dense arrays of 3D molecular nanorods or rings with an area density close to 10(10) cm(-2) were demonstrated with a pore size of 20 nm and a pitch size of 100 nm. Those engineered molecular nanostructures provide an excellent opportunity for biological applications, sensing sources of nanodevices, biochemical reactions on surfaces, and even single molecule studies. (c) 2006 American Institute of Physics.
High-sensitivity microwave vector detection at extremely low-power levels for low-dimensional electron systems
(2004-11-01)
Hsieh, WH
;
Kuan, CH
;
Suen, YW
;
Chang, SY
;
Li, LC
We present a high-sensitivity microwave vector detection system for studying the low-dimensional electron system embedded in the gaps of a coplanar waveguide at low temperatures. Using this system, we have achieved 0.005% and 0.001degrees resolutions in amplitude and phase variations, respectively, at 10 GHz in a magnetotransport measurement on a quantum-wire array with an average signal power less than -75 dBm into the sample at 0.3 K. From the measured phase variation, we can distinguish a very tiny change in the induced dipole moment of each quantum wire. (C) 2004 American Institute of Physics.
Multicolor infrared detection realized with two distinct superlattices separated by a blocking barrier
(2002-04-01)
Chen, CC
;
Chen, HC
;
Kuan, CH
;
Lin, SD
;
Lee, CP
A multicolor infrared photodetector was realized with two superlattices separated by a blocking barrier. The photoresponse is switchable between 7.5-12 and 6-8.5 mum by the bias polarity, and is also tunable by the bias magnitude in each wavelength regime. In addition, our detector exhibits advantages including little temperature dependence of the spectral response and the same order of responsivity in the two wavelength regimes. The measured peak responsivities in the two regimes are 117 mA/W at 9.8 mum under 1 V and 129 mA/V at 7.4 mum under -0.8 V, respectively. Also, the detectivities are comparable with the conventional multistack detector. The zero background peak detectivities are 2.3x10(10) cm Hz(0.5)/W at 50 K and 9.8 mum under 0.7 V, and 8.7x10(10) cm Hz(0.5)/W at 70 K and 7.4 mum under -0.7 V. (C) 2002 American Institute of Physics.
Multicolor infrared detection using two stacks of superlattice structures in a back-to-back configuration
(2000-10-02)
Hsu, MC
;
Kuan, CH
;
Wang, SY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Voltage-controlled multicolor detection with a two-stack GaAs/AlGaAs superlattice structure is reported. Each stack contains a superlattice and current blocking layers. The responsivity of each stack has a voltage-tunable spectral range and can be turned on or off by controlling the bias polarity. In a back-to-back configuration of the two stacks, a variable detection range with peak wavelength at 5.5, 6.8, 8.5, and 10.8 mu m is achieved by changing the applied voltage at 45 K. (C) 2000 American Institute of Physics. [S0003- 6951(00)05037-3].
Performance and application of a superlattice infrared photodetector with a blocking barrier
(2002-02-01)
Chen, CC
;
Chen, HC
;
Hsu, MC
;
Hsieh, WH
;
Kuan, CH
An infrared photodetector that contains a superlattice structure and a blocking barrier was investigated. The photodetector shows advantages including a low operating voltage (<0.7 V), wide detection bandwidth, flexible miniband engineering, and in particular, voltage-tunable spectral responsivity. The blocking barrier not only prohibits the dark current but also acts as a high-pass energy filter to tune the spectral responsivity. The zero background peak detectivity of our detector is 3.7x10(9) cm Hz(0.5)/W (9.7 mum) at -0.5 V and 2.2x10(10) cm Hz(0.5)/W (6.7 mum) at -0.1 V. Since the spectral responsivity at different biases is independent, temperature sensing is feasible by taking the ratio of the measured photocurrent at different biases. A demonstration of temperature sensing by using our superlattice infrared photodetector with a blocking barrier is also shown in this article. Those results show the superlattice is a simple and efficient structure for the design of a multicolor infrared photodetector. (C) 2002 American Institute of Physics.
Relaxation mechanisms of the photoelectrons in the second miniband of a superlattice structure
(2003-02-01)
Chen, CC
;
Chen, HC
;
Hsu, MC
;
Hsieh, WH
;
Kuan, CH
Photoelectron relaxation in the second miniband of a superlattice was studied with a high-pass energy filter at one end of the superlattice. By analyzing the spectral responses with different biases across the energy filter, the photoelectron distribution and relaxation in the second miniband of the superlattice can be resolved. In this paper, a model based on the rate equation is proposed to extract the related parameters of the photoelectron transport. The photoelectrons suffer from both intraminiband and interminiband relaxation. The extracted interminiband relaxation time is 11 ps, while the intraminiband one is in the sulipicosecond range. In addition, this structure can also be utilized as an infrared photodetector. Our analysis shows that the fast intraminiband relaxation is the dominant mechanism of the maximum achievable responsivity of the detector and the theoretical model not only provides the insight of the photoelectron transport in the superlattice miniband but also is useful for designing a superlattice infrared photodetector.